CODEWITHSUNDEEP
shelljq
uday8486
uday8486

Reputation: 1393

Need help in reducing array of object into a single sum

In shell script, I have below array of object:

response={
        "product": "BIG MAC",
        "objects": [
                        {
                            "qty": 10,
                            "size": 32
                        },
                        {
                            "qty": 20,
                            "size": 53
                        },
                        {
                            "qty": 10,
                            "size": 54
                        }
        ]
    }

I am writing a jq function to get total quantity.

data=$( echo $response | jq '.objects[] | .qty ' )

This gives me one line of quantities, like 

10 20 10

How do I sum these to get value:

40

Upvotes: 5

Views: 70

Answers (2)

peak
peak

Reputation: 116900

Using a stream-oriented addition function yields a solution that avoids the inefficiencies of constructing an array:

def sigma(s): reduce s as $x (0; .+$x);

sigma(.objects[] | .qty)

sigma as defined here is a good candidate for your "standard library" of jq functions.

Upvotes: 2

chepner
chepner

Reputation: 531948

Create an array and pipe that through add:

jq '[.objects[] | .qty] | add'

Using map might make this simpler, as you don't have to "index" .objects first:

jq '.objects | map(.qty) | add'

Upvotes: 5

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